This invention relates to a brush assembly for a rotatable brush in a movable sweeper which is meant to work on large areas such as airport runways.
Prior known sweepers have a rotatable cylindrical brush in which the sweepers have a rotation motor and a separate brush frame turnably mounted under the vehicle, i.e., sweeper frame. Conventionally, the brush frames have desirable working angles such as 35xc2x0 or 40xc2x0 wherein the brush is turned to throw particles either to the right or to the left in relation to the working or driving direction of the sweeper. Different brush angles are obtained by turning the brush frame around a vertical axle by means of a rotating motor and gear. Also a hydraulic cylinder is used to turn the brush frame to different brush angles. Brushes used in sweepers have very big breadths about 4-6 meters. The forces directing to the brush turning means may be substantial during the operation of sweeping and it follows that the turning means could be damaged easily. Moreover when turning the brush to a transporting position under the sweeper frame, the fixing points of one or more hydraulic cylinders have to be changed in order for the brush to be turned in the direction of the sweeper frame. Traditionally, adjustable sensors have been needed to adjust the angle positions of the brush in current brush turning equipment.
The brush assemblies with turning devices constructed according to this invention are easy to use, they are reliable and they can receive and tolerate large forces without becoming damaged. The present invention provides a remarkable improvement in the art compared with the prior sweepers.
The new turning equipment provides for the brush frame to have large turning angles, for example, at least 40xc2x0 in both directions. The turning of the brush frame from one side to the other can be changed very quickly. The working angles of the brush frame are adjustable to be the same as the angles which are achieved by means of the extreme positions of the hydraulic cylinder in the turning equipment, i.e. by means of the longest and shortest positions. Transforming the present turning device to a transporting position can be done very easily only by driving, i.e., adjusting one hydraulic cylinder to its extreme position. Further, a sensor is not needed for limiting the turning angles of the brush. As a result, the brush frame is turned to either side easily and quickly. The cylinder lengths are selected or adjusted so that desired brush angles in both directions can be obtained. The transporting position of the brush in the direction of the vehicle frame is achieved by turning the brush further by means of a second cylinder using its shortest length.